Iron pyrite is a naturally abundant and nontoxic photovoltaic material that is attractive as a photovoltaic material, e.g., due to its high absorption coefficient (˜5×105 cm−1) and energy band gap (˜0.95 eV) suitable for photovoltaic energy conversion. The estimated highest attainable efficiency of pyrite photovoltaic films is as high as that for single crystal silicon. Pyrite is thus an attractive material for use in inexpensive photovoltaic cells.